On Thu, Sep 09, 2004 at 02:36:58AM +1000, Greg Banks wrote:
> On Thu, 2004-09-09 at 01:44, Jakob Oestergaard wrote:
> > SMP systems on 2.6 have a problem with XFS+NFS.
> 
> Knfsd threads in 2.6 are no longer serialised by the BKL, and the
> change has exposed a number of SMP issues in the dcache.  Try the
> two patches at

Ok - the "small" server just hosed itself with a debug.c:106 - so I'll
be doing some testing on that one as well (after hours, today).

> 
> http://marc.theaimsgroup.com/?l=linux-kernel&m=108330112505555&w=2

Ok, I must say that mail has some *scary* comments to the patch... This
should be interesting  :)

The patch assumes some dcache code is
--------------
if (res) {
 spin_lock(&res->d_lock);
 res->d_sb = inode->i_sb;
 res->d_parent = res;
 res->d_inode = inode;
 res->d_bucket = d_hash(res, res->d_name.hash);
 res->d_flags |= DCACHE_DISCONNECTED;
 res->d_vfs_flags &= ~DCACHE_UNHASHED;
 list_add(&res->d_alias, &inode->i_dentry);
 hlist_add_head(&res->d_hash, &inode->i_sb->s_anon);
 spin_unlock(&res->d_lock);
}
--------------
While it was actually changed to
--------------
if (res) {
 spin_lock(&res->d_lock);
 res->d_sb = inode->i_sb;
 res->d_parent = res;
 res->d_inode = inode;

 /*
  * Set d_bucket to an "impossible" bucket address so
  * that d_move() doesn't get a false positive
  */
 res->d_bucket = NULL;
 res->d_flags |= DCACHE_DISCONNECTED;
 res->d_flags &= ~DCACHE_UNHASHED;
 list_add(&res->d_alias, &inode->i_dentry);
 hlist_add_head(&res->d_hash, &inode->i_sb->s_anon);
 spin_unlock(&res->d_lock);
}
--------------

I'm assuming I should just adapt this to the res->d_bucket change...

New patch against 2.6.8.1 attached.

> 
> and
> 
> http://linus.bkbits.net:8080/linux-2.5/cset@1.1722.48.23

This one is in plain 2.6.8.1 (as you said).

-- 

 / jakob